Modern media for size-exclusion chromatography combine maximum selecti
vity with high plate count to resolve solutes differing in molecular m
ass by as little as 20%. Separations of solutes differing in molecular
mass by only 10% will be very hard to accomplish even for rod-shaped
molecules. The reduced column lengths and porosity of small-particle-s
ized media unfortunately reduces the inherent resolving power to the s
ame order as traditional columns but with a substantial reduction in a
nalysis time. The use of well-calibrated columns for obtaining estimat
es of molecular mass yields a precision close to that of absolute meth
ods. The simplicity and accuracy of the integral calibration method us
ing a sample of broad molecular mass distribution makes this procedure
very suitable for manual calibration of size-exclusion columns.